Parasympatholytics

Parasympatholytics are a category of drugs that reduce the activity of the parasympathetic nervous system (PNS). They are also known as anticholinergics because they often work by blocking the action of the neurotransmitter acetylcholine in the PNS.

Mechanism of Action

Parasympatholytics inhibit the action of acetylcholine (ACh) at postganglionic sites in smooth muscle, cardiac muscle, and the central nervous system, where the neurotransmitter is released. They do this by blocking the muscarinic acetylcholine receptors, which are the receptors that ACh would normally bind to in order to exert its effects.

Uses

Parasympatholytics have a wide range of uses in medicine. They are used to treat a variety of conditions, including gastrointestinal disorders, cardiac arrhythmias, and certain types of poisoning. They are also used in anesthesia to reduce salivation and bronchial secretions, and in ophthalmology to dilate the pupils for examination.

Side Effects

Like all drugs, parasympatholytics can have side effects. These can include dry mouth, blurred vision, urinary retention, constipation, confusion, and in severe cases, delirium. Because of these potential side effects, they are used with caution in the elderly.

Examples

Examples of parasympatholytics include atropine, scopolamine, and ipratropium bromide. Atropine and scopolamine are naturally occurring substances derived from plants in the nightshade family, while ipratropium bromide is a synthetic compound.

See Also

• Sympathomimetic drug
• Parasympathomimetic drug
• Adrenergic antagonist